Surveying instrument



April 7, 1953 l.. sUvERKRQP- 2,633,639

` SURVEYING lNsTRuMEN'r Filed ct. 3o, 1945 .3 sheets-sheet 1 f @12:aLl-g.;- l' LQWSuNeAIaopf-a INVENTOR.

BY v

ATTORNEY.

April 7, 1953 L. SUVERKOP- 2,633,639

' SURVEYING INSTRUMENT Filed Oct. 30, 1945 -3 Sheets-Sheet 2 4 .B V l Ili204 INV ENTOR.

71g. 22 BY ATTORNEY.

April 7, 1953 L. suvERKRoP 2,633,639

v SURVEYING INSTRUMENT Filed 001". 30, 1945 :s sheen-sheet :s

` ATTORNEY. Q.

Patented Apr. 7, 1.953

UNITED STATES PATENT OFFICE SURVEYING INSTRUMENT Lew Suverkrop,Bakersfield, Calif.

Application October 30, 1945, Serial No. 625,549

Claims.

This invention relates to improvements in surveying instruments and moreparticularly, but without limitation, to improvements in the surveyinginstrument shown in my prior patent, No. 2,231,036, issued February 11,1941. The latter instrument is characterized as a pocket transit and thefeatures included therein resulted in a precision instrument having ahigh degree of accuracy combined with versatility and portability. Saidinstrument may be either hand-held or supported on a tripod and performsthe functions of substantially all common surveying instrumentsincluding: Transit; level, plane table alidade; compass; hand level;Abney level; clinometer; bubble sextant; and the like.

The present invention has resulted from further development of the basicinstrument described in said patent for purposes of increasing itsaccuracy, lessening its cost of manufacturing, improving the speedandconvenience of its operation, and extending the elds of usefulness ofits various functions.

One of the principal objects of kthe present invention is to provide atrough compass arranged to facilitate quickly and accurately damping theneedle thereof to bring it to rest.

Another object is to provide an improved type of pivoted compass needleand mounting therefor, whereby more accurate reading of the samerelative to an index may be achieved.

A further object of the invention is to provide in a small transit,capable of being manually supported, a sighting system including theaforementioned compass and needle, whereby the needle may be observed inrelation to the object observed and a level. y

Details of the invention as Well as details of all the foregoing objectsof the invention and other objects of the invention are described in thefollowing specification and illustrated in the a-ccompanying drawingsforming a part thereof and in which: Fig. l is an enlarged verticalcross section of ,the instrument taken on the line A-A in Fig. 6.

plan and side elevation, respectively.

Fig. 11 is a bottom plan view of the instrument.

Fig. 12 is a side elevation of the horizontal spindle per se. Y

Fig. 13 is a side elevation view of the head of the instrument showingdetails used in control and movement of the telescope about thehorizontal axis.

Fig. 14 is a sectional view of the P. D. Screw per se, taken on line B-Bof Fig. 3, said screw being used for maintaining the pupil distance ofthe eye-pieces of the instrument.

Fig. 15 is a sectional view taken on the line C-C in Fig. 4, and showingdetails of the horizontal angle clamp and mechanism for effecting slowmotion of the telescope about the vertical spindle.

Fig. 16 is a side elevation view of details comprising the verticalcircle clamp screw and shoe.

Figs. 17 and 18 are respectively detail end and side views of thevertical circle slow motion adjusting bushing.

Fig. 19 is a detached view, partially in cross section, of the mechanismfor effecting slow motion of the telescope about the horizontal axis.

Fig. 20 is a perspective view of the sight guide friction spring.

Fig. 21 is a perspective view of the level tension spring.

Fig. 22 is a diagram of a reticule pattern for the instrument.

Figures 1 through 22 illustrate a transit device comprising as statedhereinabove, a highly desirable improvement over the device forming thesubject matter 4of said aforementioned Patent No.

2,231,036 in that the improved device has greater accuracy, may beoperated withgreater speed and convenience, and has greatly extendedelds of usefulness due principally to accessories and attachmentstherefor comprising parts of the present invention.

The improved transit device, unless otherwise indicated, willhereinafter in this specification and in the appended claims be referredto as the instrument It is composed of a plurality of closely associatedand interdependent items, elements, or units which cooperate to performwith precision and accuracy those functions which any complete transitmay be expected to perform. The present instrument is capable of theaccuracy ofv precise transits, levels, etc., of much larger size and, inaddition, may be used to perform other functions such as, for example,quick sighting when held to the eye as a pair of binoculars, of whichother instruments'of larger siz .are entirely incapable.

'mese-,63e

level shown in Fig. 1 operates according to the principles given in theaforementioned patent. As shown here, it is preferably constructed oftwo glass lenses of different radii, |2| and |22, fused to a centralglass ring, |23, making a permanent, hermetically sealed closure for thebubble, liquid, and ball |24. The ball |24 is preferably a highlypolished sphere of hard, extremely dense material such as aplatinum-indium alloy. Plaster or other suitable cementing materialserves to hold the level in place.

Gomometer assembly The goniometer housing 20| is recessed to receive aflange or lip formed at the upper edge of the base |02. A gasket 202, inthe form of a rubber band, for example, seals the joint. The parts arepreferably nished togetherso that the side surfaces will be continuousand at right angles to the bottom of the instrument. The vertical sidesmay be marked with English and metric scales as indicated in Figs. 2 and4. The parts are held together by means of the vertical axis adjustingscrews 203 and nuts 204 which also serve to adjust the vertical axis ofthe instrument with respect to the bottom surface. So that the troughcompass may be opened without disturbing the vertical axis adjustment,the retaining shoes 205 and screws 206 (Figs. 3, 4 and 5) may beprovided. The retaining shoe 205 is milled to provide the concave endwith a surface adapted to the thread of the screw 203 and its diameteris suiciently less than the diameter of the hole carrying it so asreadilyto permit proper threaded contact.

A bell metal or hard bronze bushing 201 is fixed within a suitableopening within housing 20| and is provided with a tapered vertical holewhich receives the bronze vertical spindle 208 whose t within thetapered hole is adjusted by means of the vertical spindle adjustingshims 200 supporting the thrust washer 2|0 against which the shoulder ofthe spindle 208 bears. Retainlng yoke 2| I, held by screws 2|2 (Figs. 1and 8), keeps the spindle 208 in place. A lens 2|3 is held into thespindle 208 by means of split ring 2 |4 and serves a double purpose; toreduce parallax in the view of the compass and level, and to completethe seal of the base of the instrument against dust and moisture as willbeexplained in greater detail hereinafter. The shoulder of the spindle208 is toothed to engage with the geared goniometer.

The gear on the spindle 208 engages with the rst wheel 2|5 of thegoniometer. The upper end of the hub of first wheel 2 l5 has a seat anda. key to receive the disk 2|6 which is held in place by the nut 2 I1.The rst wheel rotates on the shaft 2 I8 which is supported by thegoniometer case 20| above and the goniometer plate 2|9 below, throughthe goniometerscrews 220. First wheel 2 I5 drives the first pinion'22lwhich is integrally secured to the second wheel 222, and rotates on ahub extending from the Vernier base 223. The second wheel 222 engageswith the second pinion 224 which is integral with the disk 225. Disks2|3 and 225 are iigured to indicate angle against the index figures onthe vernier plate 22B which is adjustable laterally against the disk 225and is held on the Vernier base 223 by means of the Vernier screws 221.

One part of the goniometer plate 2|9bridges across the width of theinstrument and is secured to the Vernierl base. 223 by'means ofgoniometer its 6. screws 220. The other end of the goniometer plate 2|9and the vernier base are anchored to the goniometer case 20| by means ofthree screws 228. By removing these three screws 228 and by removing thegoniometer screw 220 from the top of the goniometer case 20| thegoniometer movement as an integral unit may be removed from theinstrument.

A glass window 229 in the top of the goniometer case 20| is provided forviewing the reading on the goniometer. As shown in Fig. 7, it isApreferable to obscure part of the glass by blacking or Sandblasting Vsoas to eliminate figures not essential to the angle reading. Inthe formshown, the inner disk 2|6 indicates tens of degrees, the outer disk 225indicates single and half degrees, and the Vernier is divided toindicate units of two minutes. As shown in Fig. 7. the angle reading is272 46'. The 27 on the inner disk 2|6 has passed the small pointerformed by the black surface of the glass window 229, indicating an anglemore than 27 "tens of degrees or 270; the 2 and the following halfdegreeor 30 mark have passed the zero index mark on the Vernier, indicatingmore than 230 which must be added to the 270 previously noted, making atotal indication of more than 27230'; and on the vernier the 16graduation is indicated by one of the lines on the outer disk 225 sothat 16' must be added to the previous indication of 272 30', making atotal reading of 272 46. Accuracy and consistency in readings areconsiderably improved by applying slight frictionV to the nal rotatingmember of the goniometer as through the goniometer friction spring 230resting against the shoulder of the outer disk 225. The goniometertension spring 230 is held by the adjusting plate 23| which is attachedto the goniometer plate 2|9 by means of screws 232, one of which servesas a pivot and the other to hold the desired adjustment of tension inthe friction spring 230.

A boss with a conical recess, needle seat 233, is riveted into thegoniometer plate 2|0 and serves, with the needle lifter ||5, to securethe needle when it is oi the pivot ||0.

Head assembly pinion 303 which is free to rotate in the head body 30|and is kept there by means of the retaining pin 304. The upper end ofthe declination adjusting pinion 303 is provided with capstan holes 303as shown. The vernier plate 305 is held to the head casting by screws303 and is provided for purposes of indicating the vertical angle of anydesired setting of the telescope.

The head level case 301 carries a level vial more sensitive than theinside level |2|. One end of the head level case 301l is solid and theother end is closed by a plug 308 (Fig. 4). One end o'f the head levelcase 301 terminates in a bossin which a pivot screw 309 (Figs. 2 and 5)seats and holds the case 301 against the head 30|. The other end ofthecase 301 terminates in a lug 301 extending at a right angle to thelongitudinal axis of the level and through which the adjusting screw 3|0passes andagainst the under side of which lug a stili semi-circular'springf3|| reacts.

`rthe inner surface. cf the v'head 30| nis finished to receive thehorizontal Spindle 3&3. (Figs. 1n 12 and i3.) As shown in. 1 this is:tapered and as shownin Eig. 1.3 isf providedfwith three legs or lugswhose outer ends, are. positioned within the configuration of the recessin. the: head 3FM. As shown in Fig. lf2ll the rear` surface of thehorizontal spindle 312 is slightly tapered or beveled so that when thespindle 35M` is. fixed within the recess by means of theV spindlescrews13i3e. its horizontal axis slopes. Slightly downward from aperpendicular to the. recessed surface; than-iis,y in its` relaxedposition, the horizontal axis of `the spindle slopes. slightly below a.plane; paralieltc the horizcntail'plane of the. base; of the instrument.

rlorizontalaxis achostina.l screw-A 3: l 41 actsfagainst the naturalspring or resilienceofthe spindle 31-2 so. as to bri-ng'its horizontalaxis,- into. parallelism with the. horizontal plane; of thefbase oftheinstruinentand-tl'le setscrew 311.5 (Eig. 1') which co. acts with theunparlegV or spindle tprovides thespindle withfadditional spring;Atension as; well as retaining the: adjustment.

Vertical circle memberfl; rotateson thehorizontal spindle Si 2^. ShimwashersS l T; atbotlrends of the` spindle 3412. provide. the; nt;adnstment of the vertical circleimember-li on the horizon tallspindlell'. Provided in thicknesses; of' .3,9 2.3, ,0015, and .B053incinahboth endsl off.' the spindle, these shims fmahefitpossible to;adjust, the.: posi'.h tion ci the. vertical circle member 3m in.. in.-crementsoi .0005 inclirand',zsince.thetaperis 12110, this providesforatadjustmentabout thespininabovei The recessci the-verticalcirclemember- 3.i.6.is' providedwithl an internalgear 31.3. (Figs, 1,4. and19) intofwhich the verticalcircle slow-motionlpin.- ion 323meshes- Thevertical circleslow-motion pinion 323 rotateslwithinv-an eccentricYbushing 321` shown in-Figs. l7- and 18. The vertical. circle.

slow-motion pinion.r 32h is provided Awith a knob 32D for its rotation;is-recessed to receivethe =re tainingpin 32.2 (Fig 19e);and'zisgroovedtoreceive the ball 3:23A which. permits ittoactfeitherentirely in. or entirelyout ofengagementwith the internal gear 3I9.andYprevents damage. by partial engagement. Thel ball. 323i.;` acted upon bythe spring` 324 which isretained; by the threaded -cup.325. As shownin-Fig. 4, the clamp screw 323 in conjunction with a. split. sleevear.-rangement4 holds-the eccentric bushing; 321. after being adjusted for@propermesh of the vertical cir-cieslow-motiongpinion 32e-in theinternal. gear 313;'

As shown in., ligs; 2, 13:'-andf 16,.ans arcuate shaped brakefbloclcS21-is 'anchored in: the. recess of i the head; 331i. by means for the;screa1` 32.3. This brake-block; is fashioned; so;v as i tant: looselywithin. the. recess formed; iniv the: verticali circle member 316 but isslotted inwardzfrom itsalower.

end, as shown in Fig, i3, and is provided with a tapered threaded holeintersecting said slot near the free end thereof so that it may beexpanded bymeans of the vertical circle member friction screw 323 asindicated in Fig. 1.6. The vertical circle friction screw 329 is free torotate within the boss provided on the head 33| and is retained by meansof the screw 333. Use cf the friction screw 323 permits controlling thefreedom, of motion of the Vertical circle member or stopping it due tothe lower portion of the convex surface of brake-block 321 beingengageable with the inner surface of vertical circle member 3 I 6.

A horizontalangle slow-motion. clamp ring 332 show in Fig. 15 rotatablyand threadably carries vthe slow-motion screw 333 and the spring'plungerV33.4 which 'acts against the slows-motion pin 335 screwed intoY andstationarily carried by the head '3m (Fig. 1'). The `slow-motion ring33.v is bored to rotate with head 331 freely about the vertical spindlebushing, and is slotted and' provided with 'the Aclarnpscrew 333 sothatV the slow motion clamp. ring 332' may be tightened on the verticalspindle bushing` 2c? by means ofthe clamp lever 33.1'. A... right-handthreadv is usedY for the clamp lever 331 on the clamp screw 333, and theother end' of the clamp screw 33S is providedwth a smaller left-handthread which screws into the body of the clamp ring` 332 and' extendsbeyond for the left-hand lock nut 333; This. arrangement of rightandleft-hand threads makes it possible to adjust the clamp screw 335sothatthe clamp lever 33'? will tighten the clamp ring. 332 with. theclamp lever 333i.' conveniently located.

The horizontal slow-motion. spring' 333` held' by the threaded cup 353acts againstA the spring plunger 333. The horizontal `slow-nioti'onscrew 3.3.3 consists ci va headed pint 333" which passes through thebody of theslow-motion screw 333 where itis held by means of aslottednut 333 threadably secured to the outer end of. said, pin.

This. arrangement. serves, tor give. the. slow-motionpin1335uniform1motionandiat.thesametime/preventsunintentional removal.of the. slow-motion screw 333 from the clamp ringg3'32. Rotationof slowmotion screw 333 in=onefdirection after tightening; clamp lever 337;movesA the.l 335' and head. 30| in. one direction. and-.reverse`rota-tionf of screw. 333 Vpermits spring pressed plunger 331i` to movesaid;v pin and. head in the: opposite direction'.

Ansicht tube dill shownv in Fig;Y 4 is provided for viewingV the needle.LGS.- and-nside level. 24101 the instrument. It is helci tofthe,Verticali, circle member 31.6.bymeansof three screws :$62 and carriesthe lens ii.I andthe mirror' 534 which, withy the. mirror 331.- directsthe sight of the` observer down the hollowvervticalcolumn 208;.regardless. ofr thepositionof the'sight-.tube 49.1 .about the horizontalaxis. Sight` tube: castingy 484. is provided with-.two bosses 43|.'which? arefbushed .andboredl tcA receivethefgguide-A rods Bla-nd.' 532which support. the telescopic sight cftheV instrument.. @ne of'theseguides carriesa; safety friction-.shoe 4&5- and.. spring 436 heidi by.Athe screw 40T (Fig. 2).;

screw .body which is.l boredito receive a. Bakelite plunger.v 408!that..ris11 acted on; by a.. shortz-stii helical spring which is heldAwithin Vthe head of the screw by a cup press-fitted within the head ofthe screw 408 or held there by peening over the rim of the head of saidscrew onto said cup. This arrangement is provided so that the smoothsurface of the guide 502 will not be marred by the action of the p. d.screw 408. An annular recess in the outer surface of the p. d. screw 408midway of its ends and the retaining pin 499 received at one end withinsaid recess serve to prevent loss of the p. d. screw 408.

The two guides 50| and 502 are tapered at one end and seat into thesight body 503 where they are held by means of the screws 504. The prismbase 505 is recessed slightly on each face so as to receive thehypotenuse of each of the two Porro prisms 506. Each of these Porroprisms506, as shown in Fig, l, is held into its recess in the prism base505 by means of a retaining strip 501 which is suiliciently wide tocarry the screws 509. Two wires 508 pass over the ends of each of theretaining strips 50'Iand theends'of these wires 508 are xed in the prismbase 505 by soldering or Vother common means. Tightening the screws 509against the flat surface at the apex of each prism 506 brings theretaining strip 501 up against the Wires 508 so as to draw the prism 506down into its recessed seat in the prism base 505. The prism house I0and the telescope body 503 are drawn together against the prism base 505by means of the screws 5I I, shown in Figs.,1 and 4, which pass throughthe prism base 505.

The objective mount 5I2 carries an objective lens 5I3 (Fig. 6) which isheld in-place by means of the threaded ring 5I4 screwed intothe'objective mount 5I2. lThe screw 5I5 shown in Fig, 4 fits into ahelical recess milledin the outer surface of the objective mount 5I2,providing for focusing. The optical system includes a glass reticule 5I6with engraved stadiaand crosshairs preferably of the design shown inFig. 22. In this design the double vertical lines may be made toindicate increments of angle useful in surveying, as, for example,oneminute of arc and one mil. The reticule glass 5I6 is held in thereticule body 5II which is adjustable within the sight body 503 by meansof the reticule screws 5I8. Washers 5I9 are provided to exclude dust.The Kellner eyepieceis constructed of a body 520 which is rotatablewithin the telescope bushing 52 I. A set screw .and helical slot providefor adjustment of the eye-piece, at the same time preventing its loss.The eld lens 522 is held in place by means of the spring Yspacer 523which seats against the eye-lens mount 524 which holds the eye-lens 525.-The eye-piece V52B is screwed onto the eye-lens mount 524 and is heldthere by means of the set screw 521.

The telescope is provided with a level vial mounted in the telescopelevel tube 528. At one end a tapered boss is seated into the telescopebody 503 .and pivots telescope level 528 where it is held by means ofthe screw 529. At the other end the telescope level body is providedwith a lug and an adjusting screw 53E and a U-shaped spring 53I (Fig.2l) having apertures to receive said screw for vertically adjusting thetelescope level.

The sensitivity of the levels of the instrument is preferably asfollows: The lower element of the inside level should be of suchsensitivity as merely to indicate, when the bronze ball |24 is in thecircular level index ring, that the magnetic needle is free. The upperelement of the inside level should have a sensitivity so as convenientlyto indicate with an accuracy of 5 Vminutes of arc when the instrument ishand-held. The head level 301 should have a sensitivity of about 60seconds per division, and preferably should be of the reversion type l AWhile the gears of the goniometer assembly are manufactured to closetolerances so as to mesh precisely, slight wear existing between therespective gears does not impair the accuracy of the instrument sincerotation of the base and goniometer 'housing about the vertical axisrelativeto the sighting head or vice versa is always accomplished in onedirection only, that indicated by the respective arrows on the head andgoniometer housing (Figs. 2 and 4). Such unidirectional Vrotationrenders backlash between gears of no effect on the final results ofreadings made with the instrument. The level within the compass base isalso Vprovided with an arrow (Figs. '7, 9 and 11) to indicate thedirection in which the needle of the compass should approach the needleindex I I4 in order that the same relative rotation shall take placebetween the head and goniometer housing. Errors resulting from backlashare thus completely avoided.

While the invention and the various items and features thereof have beenillustrated and dein other ways, falling within the scope of theinvention as claimed.

What I claim is: I 1. An instrument of the class described comprising incombination, -sighting means, a trough f compass having an elongatedneedle mounted for oscillation through a limited angle about a pivot, anindex means positioned in the linedof sight of said sighting means, anda pointer connected to one arm of said needle and arranged tov move ina, plane above said index means and be viewed -through said sightingmeans relative to said index means, the side walls of said trough `ofsaid compass beingv shaped to conform substantially to the extremepositions of said needle duringv said oscillatory movement, whereby suchmovementof said needlev induces current within said walls opposing thecurrent within said needle and therebyservng to damp the motions ofthecompass needle to facilitate quickly bringing the needle to rest.

2. An instrument of the class described comprising-in combination,sighting means, a member formed from material of high electricalconductivity and having an elongated trough therein, a pointed pivotprojecting upward appreciably above the bottom of said trough, the endsurfaces of said trough yapproximating segments of a sphere the centerof which is substantially at said pivot, a magnetic compass needlearranged to be viewed through said sighting means and havingintermediate its ends and substantially labove the level thereof abearing pivotally mounted on said pivot, said trough having an outlinein plan view defined substantially by the extreme positions of saidneedle when swung in opposite directions through a limited angle,whereby oscillatory movement of the compass needle in coming to restwill induce within said trough member a secondary magnetic eld acting ina direction opposite to that of the magnetic current within said needleand serving to damp the movement of said needle to facilitate quicklybringing the needle to rest, and an elongated pointer of circularcross-section projecting from one end of and 11 above said needle, theaxis or said pointer .intersecting the point. 1 rotation or. said pivot.

3. An instrument of the class described comprising in combination,sighting means, a member formed from material oi. high electricalconductivity and having a trough therein, a. pivot fixed to andprojecting into said. troueh'from the base thereof, and a magneticcompass needle pivotally mounted on said pivot and having a pointer onone arm thereof, in radial alignment with the point of said pivot andarranged to be viewed through said sighting. means, said trough havingan elongated outline in plan view tapered inward from opposite endstoward .the .center and arcuate at the ends thereof and defined.substantially by the extreme positions of the` sides and ends of saidneedle when swung in opposite. directions through a limited angle,whereby oscillatory movement of the compass needle in coming to restwill induce within theV wallsV of said trough member a secondarymagnetic eld acting in adirection opposite to that QI the magneticcurrent within said needle and serving to. dampthemovement of saidneedle to facilitate quicklybringing the needle to rest.

4. A compass comprisingv in combination, a pivot, a magnetic needlehaving a bearing inter.-V mediately of its endsv and spacedsubstantially above the longitudinal axis of said needle, said bearingresting upon. said pivot to support said needle for oscillation androtation about said pivot, and a pointer Supported .by one endof'saidneedle and the free end projecting in parallelism to said needle, saidpointer being circular in crosssection and the axis o f said free endthereof in? tersecting the point of rotation of said bearing about saidpivot.

5. An instrument oi the class described comprising in combination,sighting means, an index means of predetermined width in the line ofvision of said sighting means, andv apivoted compass needle having apointer circular in crosssection arranged to be viewed through Saidsigh-ting means vertically from above. and in relation to said indexmeans, said pointer being movable in a plane above said index. means andhaving. a diameter precisely equal to the width of said indeX means tofacilita-te visually aligning it and said needle pointer exactly and theaxis of `Said pointer extending through the point of rotation of saidneedle about its pivot.

LEW SUVERKROP- vREFEREIST(IES CITED The following references. are ofrecord in the ille of this patent:

Number.

Number PATENTS Name Date Capel; Feb. 4, 1879 Randolph Nov. 9, 1880Blattner Sept. 12, 1882 Gurley et al Oct. 16, 1883 Randolph Apr. 22,1884 Warner Oct. 15, 1889 Seltmann et al Feb. 24, 1891 Paoli May 26,1891 Randolph Mar. 1, 1892 Ritchie Aug. 15, 1893 Hooper Feb. 5, 1895Geier Nov. 8, 1904 Hutchins Mar. 6, 1906 Reichenbach et al. Dec. 25,1906 Saegmuller et al. Apr. 26, 1910 Berger June 13, 1911 Graves Aug.20, 1912 Odhner July 22, 1913 Lyford et al July 28, 1914 Churchill etal, May 9, 1916 Berger Deo. 19, 1916 Olan June 24, 1919 Rafl'o Aug. 19,1919 Ahmels Apr. 11, 1922 Banoalari' Dec. 19, 1922 Vaughan Feb. 20, 1923Warburg Nov. 20, 1928 Sundhaussen June 3, 1924 Windham July 29, 1924 VonGruber Apr. 3, 1928 Salzgeber Apr. '7, 1931 Steinle Feb. 14, 1938Svenson May 16, 1933 Kiefer Aug. 7, 1934 Hull Sept. 4, 1934 Karnes Sept.18, 1934 Faus May 28, 1934 Spiller July 16, 1935 Owen Nov. 26, 1985 WestNov. 10, 1936 Markert Feb. 1, 1938 Winterer et al Mar. 22, 1938 MartinAug. 23, 1938 Suverkrop Feb. 1l, 1941 Blasohke Dec. 15, 1942 Boughton etal. May '1, 1946 FOREIGN PATENTS Country Date Great Britain Nov. 8, 1907Great Britain Nov. 28, 1907 Norway Sept. 8, 1947 France. Jan. 17, 1919France May 10, 1924

